Daily bisphenol A excretion and associations with sex hormone concentrations: results from the InCHIANTI adult population study.

Background: Bisphenol A (BPA) is a high production volume chemical widely used in packaging for food and beverages. Numerous studies have demonstrated that BPA can alter endocrine function in animals, yet human studies remain limited.

Objective: We estimated daily excretion of BPA among adults and examined hypothesized associations with serum estrogen and testosterone concentrations.

Methods: We conducted cross-sectional analyses using data from the InCHIANTI Study, a prospective population-based study of Italian adults. Our study included 715 adults between 20 and 74 years old. BPA concentrations were measured by liquid chromatography-mass spectrometry in 24-hr urine samples. The main outcome measures were serum concentrations of total testosterone and 17beta-estradiol.

Results: Geometric mean urinary BPA concentration was 3.59 ng/mL [95% confidence interval (CI), 3.42-3.77 ng/mL], and mean excretion was 5.63 microg/day (5th population percentile, 2.1 microg/day; 95th percentile, 16.4 microg/day). We found higher excretion rates among men, younger respondents, and those with increasing waist circumference (p = 0.013) and weight (p = 0.003). Higher daily BPA excretion was associated with higher total testosterone concentrations in men, in models adjusted for age and study site (p = 0.044), and in models additionally adjusted for smoking, measures of obesity, and urinary creatinine concentrations (beta = 0.046; 95% CI, 0.015-0.076; p = 0.004). We found no associations with the other serum measures. We also found no associations with the primary outcomes among women, but we did find an association between BPA and SHBG concentrations in the 60 premenopausal women.

Conclusion: Higher BPA exposure may be associated with endocrine changes in men. The mechanisms involved in the observed cross-sectional association with total testosterone concentrations need to be clarified.